peh-amg

I recently bought a C250 coupe for my wife and we both love it but the fuel economy is terrible. Granted the engine is new (only 500 miles now) and I live in Wisconsin so its cold but running around town and driving very gently we only see 16 - 17 mpg. On the same short trips my C63 gets 16 mpg!

I've also noticed that the coolant temp in the C250 takes a long time to reach full operating temp. When the engine is warming up and I stop at a traffic light the coolant temps starts to drop lower! Doesn't make sense.

Anybody seeing similar things with their C250?

Also, what MPG are you getting around town?

datescamelsoil

i get around 25-30MPG in city when averaging 30-40 km/h never passed 3.5k RPM
and around 22.5MPG on highways ( 160-240 km/h for 120 km ) like endurance tests but never passed 5k RPM and mostly around 3.5k RPM


regarding the temp... i guess ur car is so cold so the ecu dumps loads of fuel to heat up the cats... maybe a bad thermostatic valve.

peh-amg

I agree with you that it could be the thermostat. I think this is why it cools down when I stop at a red light. It should actually get hotter when stopped with no air going through the radiator.

Dealer doesn't want to do anything due to no CEL's.

datescamelsoil

when i get down to 100km/h after cruisng on 200km/h for few mintues the temp drops down to 80 but soon gets back to 92 again in 10 seconds... i think the thermostat response time for adjustment is a lil bit high.

maybe we have a bad batch of thermostats...

anyhow ,don't drive it, low temps will kill ur engine sooner than u think....
document the thing with video and send it to MBUSA

Regards,

dol4er

When mine was brand new, I was also getting the same figures for city driving.
Now I get 23-26 mpg (10 l/100km), average speed 25km/h.
On the highway, I get 33-36 mpg.

peh-amg

Your fuel economy is what I was expecting from my wifes car but I probably need to get it broken in and wait for warmer temps before I see these numbers.

However, I will pursue the dealer about the possibility of a problem with my thermostat.

Would appreciate it if other owners would post their MPG's on this thread.

Thanks

sheizfreshhh

I get around 20-25 city and 28-33 highway. Currently have 2200 miles .

AllEyesOnMe

City: ~18 mpg
Highway: ~30 mpg
Combined: 22 mpg

The first 2 numbers are from resetting the mpg gauge.
On a scale of aggressive-ness driving, it'd be an 3/5, 5 being flooring it everywhere.

andrew e coupe

~ mostly city driving for me... 19 - 20 mpg.

AV1

Interesting numbers there with the 1.8ltr C250 petrol engine, just for comparison for the 2.1ltr C250 diesel engine (CDI) just done a conversion to imperial measure and I'm averaging a combined cycle of 43mpg and it's increasing as the mileage builds up and the engine settles in will be able to achieve over 50mpg on a steady highway run

We're lucky in some Countries/markets to have the choice of both petrol and diesel engine options

peh-amg

43 MPG is impressive.

AV1

Yes it is and all the more so when you consider the power and torque output generated from this 2.1ltr twin turbo IL4 for the amount of diesel fuel used (which also results in better performance than the C250 petrol variant) and the extra weight of the diesel engine unit which makes the overall vehicle weight of a C250 diesel Coupe variant around 110kg or 220lb heavier than for the C250 petrol variant, given vehicle overall weight were equal it would be even further ahead.

It's one of the main reasons I opted for the diesel option in the C Coupe pity though MB only offers one diesel engine choice for the C Coupe

The Fonz

I have the 2.1l diesel and get 4.6l/100km which is something like 51MPG Highway and cruise set at 100 kmph (60mph) with a diesel box which raises torque to 590Nm and power to 175Kw. even around town mostly stop start traffic i get 8.2l/100km (28 - 29mpg) and with the diesel box and all that torque i win at the traffic light derby also.
Diesel was a great choice as far as i am concerned.

AV1

Could not agree more, as said choice wise it's a no brainer between a C250-CDI vs the CGI or petrol, especially also considering that they're both priced exactly the same as well = win win for the diesel

As far as tuning I'm still looking into that one, there are a variety of more sophisticated tuning 'modules' starting to appear on the market now for the diesels which offer boost and further timing tuning rather than just fuel rail pressure increases from typical piggy back boxes, the Brabus unit seems to deliver very impressive results not from the advertised numbers but from actual driving behind the wheel it turns an already powerful MB diesel into a real beast and consumption is still fantastic

AndyAtlanta

That are great numbers compared to my experience. My C250 has about 3k miles and I get about 16 mpg city and 27 mpg tops in Atlanta highways which usually ride around 75-85mph. Around 85 the mpg drops to about 25 mpg or less. At first I thought it could be the 18 AMG tires creating more friction but in reality those MB Mpg city/hwy figures must have been achieved driving it like and old lady.

The issue I think is that small engine married with the turbo, while it loves to rev high to keep up with the traffic and gives strong torque I think that kills the mpg. If they had placed a slightly bigger four they would have done better at the fuel savings. Another thing I noticed, they cut a lot of corners in the cost of the coupe vs the pre-2012 c300 sedans and initially I didn't notice.

I used to have a c300 and the city figures where moderately lower giving me about 15mpg city but on the highway I would get more depending on the speed since I had the 7speed and could go up to 90 keeping the 27mpg or more.

If I were to purchase this car again or make a recommendation, I would definitely recommend the C350 since gas savings in this car, at least for me, wasn't worth it for the lost end horsepower and V6 growl.

AV1

It is an interesting choice in the petrols, I too agree that the 1.8ltr petrol of the C180 and C250 petrols is a little small and lacking but given more time I'm sure more tuning applications will become available albeit at the expense of economy, just comes down to what one wants out of this car

AkaSigFreak

I get better highway mileage in Sport Mode. I tested it in Economy and was getting 25-27 at 80 mph and in Sport was getting 28-31 at 80 mph. I've been having fun driving aggressively since I got the Burger Motorsports JB+ and the Intake so my city mpg has been low (around 16-18 mpg).

AllEyesOnMe

How is that possible though, that S in highway gets more MPG than E? Highway means staying mostly in 7th gear, which would make no change if you're driving at a constant speed?

Anyways, I'm getting about 27mpg driving at 70mph, and I think almost 30 mpg driving at 60-65ish. This is with 80% highway/20% street.

I have JB tune and intake if that makes any difference

AkaSigFreak

It doesn't make any sense to me either. When I tested it- I was cruising on the open highway in E-Mode. I reset the Average MPG and noted the number. I had to stop and this time I went into S-Mode and reached the same speed, reset the Average, and once again noted the figure. It is probably not the most scientifically accurate way to determine the MPG but that's how I came up with the figures. I also have the JB+ and Intake.

crdcz03

so JB+ makes the mileage better too? its like there are no cons and all pros

AkaSigFreak

I definitely DOESN'T make it better all of the time. My City MPG is horrible due to "Spirited" driving. I can't help it. The sound of the Intake "Sucking", the Exhaust note, and the Turbo "Woosh" sound amazing.
Sorry you didn't get the chance to drive it yesterday. We'll meet up soon.

Jbs210

Hi. I recently bought a C250 & my gas mileage is crazy low. I get 16.5 mpg. I don't understand how this is happening when the car is advertised at 22 mpg. I only drive in the city so i didnt expect more than advertised. I'm scheduled to bring it in for service next week & it's only a month old! Any thoughts?
Thanks!

CPatrick

My commute to work each day is an hour (54 miles), so I'm racking up at least 110 miles/day. Depending upon where I fill up, I get between 28 and 32.4 miles/gallon. My range with a full tank is typically 450 miles.

I currently have 13,300 miles on the car, and I didn't find that the BMS Air Intake and/or BMS JB+ increased fuel efficiency.

ralawren

C350 Coupe owner - drove 670 miles fom Raleigh to Syracuse and got 31.4 mpg northbound and 32 mpg southbound. Drove 70-80 mph, averaged 67 mph for the entiretrip. The 3.5L 6 is hardly working and the 2012+ 7g transmission is extremely efficient.

I realize the extra low end torque fom th turbo helps around town but once. Get the revs up to 4k the car flys and sounds awesome......

Rafiki

i get 40mpg from my 98 civic and 15 form my 63